Table 1 Descriptive characteristics of cardiac surgery patients stratified by sex and surgical group
|  | Female N = 28,437 | Male N = 82,993 | Total N = 111,430 | Standardized Difference |
|---|---|---|---|---|
Patient factors | ||||
 Age | 69 (61–76) | 66 (59–74) | 67 (59–74) | 0.24 |
 Atrial fibrillation | 4,157 (14.6%) | 8,934 (10.8%) | 13,091 (11.7%) | 0.12 |
 Anemia | 2,999 (10.5%) | 4,806 (5.8%) | 7,805 (7.0%) | 0.17 |
 Asthma | 5,323 (18.7%) | 8,770 (10.6%) | 14,093 (12.6%) | 0.23 |
 CAD | 14,351 (50.5%) | 46,061 (55.5%) | 60,412 (54.2%) | 0.1 |
 Stroke | 806 (2.8%) | 2,090 (2.5%) | 2,896 (2.6%) | 0.02 |
 Dementia | 83 (0.3%) | 181 (0.2%) | 264 (0.2%) | 0.01 |
 Diabetes | 12,391 (43.6%) | 34,881 (42.0%) | 47,272 (42.4%) | 0.03 |
 Dialysis | 475 (1.7%) | 1,299 (1.6%) | 1,774 (1.6%) | 0.01 |
 Hypertension | 23,961 (84.3%) | 68,458 (82.5%) | 92,419 (82.9%) | 0.05 |
 Chronic liver disease | 216 (0.8%) | 617 (0.7%) | 833 (0.7%) | 0 |
 Myocardial infarction | 7,147 (25.1%) | 23,326 (28.1%) | 30,473 (27.3%) | 0.07 |
 PVD | 1,858 (6.5%) | 5,253 (6.3%) | 7,111 (6.4%) | 0.01 |
 Primary cancer | 661 (2.3%) | 2,118 (2.6%) | 2,779 (2.5%) | 0.01 |
 Secondary cancer | 109 (0.4%) | 246 (0.3%) | 355 (0.3%) | 0.01 |
 COPD | 3,456 (12.2%) | 8,168 (9.8%) | 11,624 (10.4%) | 0.07 |
bChronic kidney disease | ||||
 Stage 1 | 6,149 (21.6%) | 22,947 (27.6%) | 29,096 (26.1%) | 0.14 |
 Stage 2 | 10.947 (38.5%) | 32,419 (39.1%) | 43,366 (38.9%) | 0.01 |
 Stage 3 | 6,249 (22.0%) | 13,286 (16.0%) | 19,535 (17.5%) | 0.15 |
 Stage 4 | 1,035 (3.6%) | 1,991 (2.4%) | 3,026 (2.7%) | 0.07 |
 Stage 5 | 344 (1.2%) | 903 (1.1%) | 1,247 (1.1%) | 0.01 |
 CCI ≥ 2 | 9,027 (31.7%) | 23,775 (28.6%) | 32,802 (29.4%) | 0.07 |
 Rural | 4,237 (14.9%) | 12,539 (15.1%) | 16,776 (15.1%) | 0.01 |
 Income quintile | ||||
 Q1 | 6,284 (22.2%) | 14,752 (17.8%) | 21,036 (18.9%) | 0.11 |
 Q2 | 6,052 (21.4%) | 16,582 (20.0%) | 22,634 (20.4%) | 0.03 |
 Q3 | 5,677 (20.0%) | 17,057 (20.6%) | 22,734 (20.5%) | 0.01 |
 Q4 | 5,268 (18.6%) | 17,156 (20.7%) | 22,424 (20.2%) | 0.05 |
 Q5 | 5,055 (17.8%) | 17,162 (20.7%) | 22,217 (20.0%) | 0.07 |
Body mass index | ||||
  ≤ 25 | 8,206 (28.9%) | 19,187 (23.1%) | 27,393 (24.6%) | 0.13 |
 26–30 | 8,574 (30.2%) | 32,880 (39.6%) | 41,454 (37.2%) | 0.2 |
  ≥ 31 | 10,274 (36.1%) | 26,736 (32.2%) | 37,010 (33.2%) | 0.08 |
LVEF | ||||
  < 20% | 241 (0.8%) | 1,509 (1.8%) | 1,750 (1.6%) | 0.08 |
 20%—34% | 1,715 (6.0%) | 7,190 (8.7%) | 8,905 (8.0%) | 0.1 |
 35%—49% | 4,378 (15.4%) | 17,549 (21.1%) | 21,927 (19.7%) | 0.15 |
  ≥ 50% | 21,233 (74.7%) | 54,069 (65.1%) | 75,302 (67.6%) | 0.21 |
Smoking status | ||||
 Current | 4,523 (16.1%) | 16,682 (20.3%) | 21,205 (19.2%) | 0.11 |
 Former | 6,799 (24.1%) | 31,231 (38.0%) | 38,030 (34.5%) | 0.3 |
 Never | 16,554 (58.8%) | 33,472 (40.7%) | 50,026 (45.3%) | 0.37 |
 Frailty | 2 (0–5) | 1 (0–3) | 1 (0–4) | 0.19 |
 Preop DAH (3m—1d) | 89 (82–92) | 89 (83–92) | 89 (83–92) | 0.04 |
Surgery | ||||
 Surgery duration (min) | 268 (223–323) | 273 (230–326) | 271 (228–325) | 0.07 |
 Re-do surgery | 833 (5.5%) | 1,835 (4.4%) | 2,668 (4.7%) | 0.05 |
 Preop ICU level care | 15,913 (56%) | 47,358 (57.1%) | 63,271 (56.8%) | 0.02 |
 Elective | 17,975 (63.2%) | 51,316 (61.8%) | 69,291 (62.2%) | 0.03 |
 Urgent/Emergent | 10,462 (36.8%) | 31,677 (38.2%) | 42, 139 (37.8%) | 0.03 |
 Surgical group | ||||
 Combined surgeries | 7,393 (26.0%) | 16,352 (19.7%) | 23,745 (21.3%) | 0.15 |
 Isolated non-CABG procedure | 6,933 (24.4%) | 10,298 (12.4%) | 17,231 (15.5%) | 0.31 |
 Isolated CABG | 14,111 (49.6%) | 56,343 (67.9%) | 70,454 (63.2%) | 0.38 |
Hospital | ||||
 Teaching hospital | 17,634 (62.0%) | 50,531 (60.9%) | 68,165 (61.2%) | 0.02 |
 ICU Beds | 61 (35–77) | 60 (35–74) | 60 (35–74) | 0.03 |
 Surgical Beds | 131 (84–210) | 131 (84–176) | 131 (84–176) | 0.01 |
 Total Beds | 367 (288–514) | 367 (291–513) | 367 (291–513) | 0 |
Outcomes | ||||
 30-day mortality | 418 (1.5%) | 778 (0.9%) | 1,196 (1.1%) | 0.05 |
 90-day mortality | 670 (2.4%) | 1,238 (1.5%) | 1,908 (1.7%) | 0.06 |
 ICU LOS (h) | 47 (25–95) | 37 (23–75) | 42 (24–78) | 0.17 |
 ALC patient | 1,380 (4.9%) | 2,155 (2.6%) | 3,535 (3.2%) | 0.12 |
 Postop LOS (d) | 7 (6–10) | 6 (5–8) | 6 (5–9) | 0.38 |
 Major complications | 6,148 (21.6%) | 14,132 (17.0%) | 20,280 (18.2%) | 0.12 |
 30-day hospital readmission | 3840 (13.5%) | 8293 (10.0%) | 12,133 (10.9%) | 0.11 |
 90-day hospital readmission | 5681 (20%) | 12,357 (14.9%) | 18,038 (16.2%) | 0.13 |
 180-day hospital readmission | 6998 (24.6%) | 15,697 (18.9%) | 22,695 (20.4%) | 0.14 |
 aDAH30 | 22 (16–24) | 23 (20–25) | 23 (19–25) | 0.42 |
18.5 ± 7.8 | 20.8 ± 6.7 | 20.2 ± 7.1 | 0.31 | |
 aDAH90 | 81 (74–84) | 83 (79–85) | 83 (78–85) | 0.42 |
73.0 ± 20.7 | 77.5 ± 16.8 | 76.3 ± 18.0 | 0.24 | |
 aDAH180 | 171 (162–173) | 173 (168–175) | 172 (166–174) | 0.41 |
156.5 ± 39.8 | 163.4 ± 32.0 | 161.6 ± 34.2 | 0.19 | |